Color-filter on Array (COA) is a technology that integrates a color filter substrate with an array substrate. It forms a color filter layer on the signal line layer of an array substrate to make up the array substrate.
For a completed array substrate, if the signal line in the array substrate is disconnected, the array substrate is usually maintained in the following manner: firstly boring a hole in the color filter layer until the hole reaches the signal line layer, and then performing continuous deposition at the position where the hole is bored using particles (for example, tungsten powder) generated by a photothermal reaction to form a film, thereby connecting the disconnected signal line.